1. Field of the Invention
The present invention relates to a substrate and a method for making the same, and more particularly to a coreless substrate and a method for making the same.
2. Description of the Related Art
FIGS. 1 and 2 show schematic views of a method for making a conventional substrate. First, a core substrate 11 is provided. The core substrate 11 comprises a core layer 111, a first circuit layer 112, a second circuit layer 113 and at least one via 114. The core layer 111 comprises a first surface 1111 and a second surface 1112. The first circuit layer 112 is disposed on the first surface 1111 of the core layer 111. The second circuit layer 113 is disposed on the second surface 1112 of the core layer 111. The via 114 penetrates the core layer 111, and electrically connects the first circuit layer 112 to the second circuit layer 113.
A first dielectric layer 12 and a second dielectric layer 13 are formed on the first circuit layer 112 and the second circuit layer 113, respectively. The first dielectric layer 12 has at least one first opening 121 so as to expose the first circuit layer 112, and the second dielectric layer 13 has at least one second opening 131 so as to expose the second circuit layer 113. Afterward, a first conductive metal 14 is formed on the first dielectric layer 12 and the exposed first circuit layer 112, and a second conductive metal 15 is formed on the second dielectric layer 13 and the exposed second circuit layer 113. Finally, a patterning process and a plating process are conducted so as to form a third circuit layer 16 and at least one first conductive hole 17 on the first conductive metal 14, and a fourth circuit layer 18 and at least one second conductive hole 19 on the second conductive metal 15, and a conventional substrate 1 is formed.
The method for making the conventional substrate 1 has the following disadvantages. The method starts with providing a core substrate 11 which has a certain thickness, so the conventional substrate 1 has low density of layout. Moreover, because the inner structure of the core substrate 11 is formed by drilling, plating, plugging and layout forming, the procedure is complicated and the manufacturing cost is high.
Therefore, it is necessary to provide a coreless substrate and a method for making the same to solve the above problems.